Novel heroin injection practices: implications for transmission of HIV and other bloodborne pathogens

Prevalence and Correlates of the Use of Prefilled Syringes Among Persons Who Inject Drugs in San Diego, CA

Persons who inject drugs (PWID) are at increased risk for blood-borne virus (BBV) infections and overdose resulting from high-risk injecting practices. Studies of prefilled syringe use ([PFSU] using a syringe that already contained drug solution when it was obtained by the user), an injection practice previously described in Eastern Europe, suggest that it increases susceptibility to BBV. However, little is known about this practice in the USA. Data were obtained from an ongoing cohort study of PWID to determine the prevalence and assess correlates of PFSU in San Diego, CA. Baseline interviews assessed socio-demographics and drug use behaviors. Logistic regression was used to identify factors independently associated with ever using a prefilled syringe (yes/no). Participants (n = 574) were predominately males (73.9%) and white (50.9%) with a mean age of 43.4 years (range 18-80); 33.3% reported ever using prefilled syringes, although only 4.9% reported use in the past 6 months. In multivariable analyses, PFSU was independently associated with ever having a rushed injection due to police presence [adjusted odds ratio (AOR) = 2.51, 95% CI 1.66, 3.79], ever being in prison (AOR = 1.80, 95% CI 1.23, 2.63), injecting most often in public versus private places in the past 6 months (AOR = 1.66, 95% CI 1.11, 2.48), and injecting drugs in Mexico (AOR = 1.70, 95% CI 1.16, 2.49). Results indicate that a history of PFSU is common and associated with environmental factors that may also increase risk for adverse health outcomes. Studies are needed to better understand PFSU in order to develop interventions to prevent adverse outcomes associated with their use.

Prevalence and correlates of HCV monoinfection and HIV and HCV coinfection among persons who inject drugs in Vietnam

BACKGROUND

Vietnam bears a high burden of hepatitis C virus (HCV) and HIV infection among persons who inject drugs (PWID). The high prevalence of HCV and HIV occurs in a context of stigma and limited preventive interventions for PWID.

OBJECTIVES

This study aims to estimate the prevalence of HCV, HIV, and HIV/HCV coinfection among PWID and to explore their associations with lifetime injection behaviors.

METHODS

A total of 1434 PWID were recruited from the Thai Nguyen Province of Vietnam between 2005 and 2007. Participants responded to a structured questionnaire and provided blood samples at baseline. A cross-sectional analysis of data collected at baseline was carried out. Factors associated with HCV monoinfection and HIV/HCV coinfection were evaluated by multinomial logistic regression.

RESULTS

The prevalences of HIV and HCV were 35.1 and 88.8%, respectively, and the prevalences of HIV/HCV coinfection and HCV monoinfection were 34.8 and 53.9%, respectively. After adjusting for confounders in multivariate analysis, ever reusing a syringe and needle was found to be significantly associated with HIV monoinfection [adjusted odds ratio (AOR), 3.13; 95% confidence interval (CI), 1.99-4.94] and HIV/HCV coinfection (AOR, 3.34; 95% CI, 2.02-5.51). Ever sharing diazepam or novocaine was also found to be significantly associated with HIV monoinfection (AOR, 2.14; 95% CI, 1.38-3.32) and HIV/HCV coinfection (AOR, 2.47; 95% CI, 1.57-3.90).

CONCLUSION

Our findings demonstrate a high burden of HIV and HCV infection among PWID in Vietnam. Lifetime injection behaviors, including sharing of diazepam or novocaine, may account for the high prevalence of HIV and HCV. Improving prevention and ensuring access to care remain critically important for this vulnerable population.

The impact of social, structural and physical environmental factors on transitions into employment among people who inject drugs

Despite growing awareness of the importance of context for the health of people who use drugs, studies examining labour market outcomes have rarely considered the role that physical, social and structural factors play in shaping labour market participation among drug users. Using discrete time event history analyses, we assessed associations between high-intensity substance use, individual drug use-related risk and features of inner-city drug use scenes with transitions into regular employment. Data were derived from a community-recruited cohort of people who inject drugs in Vancouver, Canada (n = 1579) spanning the period of May 1996-May 2005. Results demonstrate that systematic socio-demographic differences in labour market outcomes in this context generally correspond to dimensions of demographic disadvantage. Additionally, in initial analyses, high-intensity substance use is negatively associated with transitions into employment. However, this negative association loses significance when indicators measuring exposure to physical, social and structural features of the broader risk environment are considered. These findings indicate that interventions designed to improve employment outcomes among drug users should address these social, structural and physical components of the risk environment as well as promote the cessation of drug use.

Morphine modulation of toll-like receptors in microglial cells potentiates neuropathogenesis in a HIV-1 model of coinfection with pneumococcal pneumoniae

Chronic drug users account for a third of all cases of AIDS in the United States and the progression to AIDS dementia is accelerated in opiate drug abusers. Clinically, microglial activation better correlates with HIV-associated neurocognitive disorders (HAND) than productive HIV-1 infection in the CNS. Moreover, pneumococcal pneumonia is the most common opportunistic infection in individuals with HAND. We show that coinfection with Streptococcus pneumoniae may be a contributing factor in the increased prevalence of HAND in the opioid-dependent population. To date, there have been no studies published implicating the Toll-like receptors (TLR) in the neurocognitive disorders associated with NeuroAIDS in the context of opportunistic infection. Our studies show for the first time, in a morphine-dependent model, synergistic increase and activation of TLR expression in the presence of HIV-1 protein TAT and S. pneumoniae with a significant increase in proinflammatory cytokines (IL-6, TNF-α) levels. Furthermore, concurrent increases in reactive oxygen species and nitric oxide production leading to increased caspase 3 activation are also observed in both murine and human microglial cells. These effects are recapitulated with TLR 2, 4, and 9 cognate ligands (Pam3CSK4, LPS, and CpG) and significantly attenuated in TLR 2 and 4 knock-out mice and TLR2/4 double knock-out mice. Therefor, our findings clearly suggest for the first time that activation of TLRs on microglia cells by morphine and TAT in the context of S. pneumoniae infection may be a potential mechanism for the increased prevalence of HAND in HIV-infected opioid-dependent patients.

Flashblood: blood sharing among female injecting drug users in Tanzania

AIMS

This study examined the association between the blood-sharing practice of 'flashblood' use and demographic factors, human immunodeficiency virus (HIV) status and variables associated with risky sex and drug behaviors among female injecting drug users. Flashblood is a syringe-full of blood passed from someone who has just injected heroin to someone else who injects it in lieu of heroin.

DESIGN

A cross-sectional study.

SETTING

Dar es Salaam, Tanzania.

PARTICIPANTS

One hundred and sixty-nine female injecting drug users (IDUs) were recruited using purposive sampling for hard-to-reach populations.

MEASUREMENTS

The association between flashblood use, demographic and personal characteristics and risky sex and drug use variables was analyzed by t-test and chi(2) test. The association between flashblood use and residential neighborhood was mapped.

FINDINGS

Flashblood users were more likely to: be married (P = 0.05), have lived in the current housing situation for a shorter time (P < 0.000), have been forced as a child to have sex by a family member (P = 0.007), inject heroin more in the last 30 days (P = 0.005), smoke marijuana at an earlier age (P = 0.04), use contaminated rinse-water (P < 0.03), pool money for drugs (P < 0.03) and share drugs (P = 0.000). Non-flashblood users were more likely to live with their parents (P = 0.003). Neighborhood flashblood use was highest near downtown and in the next two adjoining suburbs and lowest in the most distant suburbs.

CONCLUSIONS

These data indicate that more vulnerable women who are heavy users and living in shorter-term housing are injecting flashblood. The practice of flashblood appears to be spreading from the inner city to the suburbs.

Nonmedical use of promethazine hydrochloride among heroin injectors in Vietnam: unrecognized risks and unintended consequences

BACKGROUND

Surveillance studies have noted intravenous injection of promethazine hydrochloride (PHC) among populations that use heroin in south and southeast Asia. However, little is known about onset and initiation of PHC use and its relationship to habitual heroin use.

METHODS

As part of a longitudinal study of heroin initiation, a sample of 179 new heroin users, aged 15-27 years, were interviewed between October 2005 and December 2006 in Hanoi, Vietnam. Cox proportional hazard regression analysis was used to characterize age at promethazine initiation and its association with relevant covariates.

RESULTS

76% reported lifetime use of PHC. Mean age of PHC initiation was 21.3 years, on average 6 months following onset of heroin injection. In multivariate analysis, lifetime use of diazepam [HR = 1.69 (1.17, 2.44); p-value = .01] and injecting heroin for more than 1.58 years [HR = 1.46 (1.04, 2.06); p-value = .03] were associated with PHC initiation.

CONCLUSION

Intravenous injection of PHC is a relatively common practice among young injection heroin users in Hanoi, Vietnam who use it on a situational basis to substitute for heroin (when heroin is not available or when heroin is too costly) or to augment the effects of an inadequate heroin dosing (delaying onset of heroin withdraw). Existing drug prevention strategies in Vietnam are focused primarily on heroin and most new heroin users initiate PHC use without prior knowledge of its high risk for serious vein damage. Future research is needed on the PHC use among heroin users, including long-term medical consequences of PHC exposure.

Prevalence and incidence of HCV infection among Vietnam heroin users with recent onset of injection

HCV infection continues to spread at an alarming rate among IDU populations. The available evidence suggests that HCV is acquired relatively quickly following onset of injection. However, there are few prospective studies of HCV acquisition, particularly among IDU populations in resource-poor settings. A sample of young male heroin injectors with recent onset of injection (<4 years) was recruited in Hanoi, Vietnam for a prospective assessment of the early course of injection (n = 179). Both behavioral and biological assessments (including detailed retrospective assessment of injection initiation) were conducted at baseline and repeated at 6-month intervals for a period of 16 months. Variables associated with HCV infection (p value < 0.05) in bivariate analyses were considered for inclusion in logistic regression models to identify risk factors independently associated with HCV infection. HCV incidence was calculated by using the incidence density approach and was expressed in terms of person-years of observation. The baseline of prevalence of HCV was 46%. HCV significantly increased in relation to time since first injection, from 30% in subjects with </=10 months of injection risk to 70% in subjects with >/=30 months injection risk (p value = 0.0005). In multivariate logistic regression analysis, increasing age, incarceration in a drug detention facility (OR = 2.54; 95%CI 1.05, 6.15), and time since first injection remained significantly associated with HCV infection. Use of injection as primary mode of administration (OR = 2.56; 95%CI 0.98, 6.69) achieved marginal significance. After 16 months of follow-up, the incidence rate of HCV was 23.35 per 100 person-years and the mean time between first injection and first positive HCV test was 1.2 years. HCV is acquired much more rapidly among new injector populations than previously recognized, demonstrating the need for early behavioral intervention among new heroin-user populations. Particularly critical are interventions that target new heroin user populations, including interventions that improve understanding of viral transmission dynamics, that promote alternative strategies for drug sharing, and that delay initiation of injection.

Endogenous opiates and behavior: 2007

This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.